ACID

A class of chemical compounds whose aqueous solution has a pH less than 7.0.

ACTIVE OIL

Oil which contains chemically active ingredients to prevent metal-to-metal friction when the pressures become too great for the natural film strength of the oil.

ADDITIVE

A chemical compound added to a lubricant or metalworking fluid for the purpose of imparting new properties or for enhancing those properties for which it already has.

ALKALINE

A class of chemical compounds whose aqueous solution has a pH greater than 7.0.

ANNEALING

A controlled heating and cooling cycle to remove stress, induce softness, or refine the structure of a metal.  Annealing generally imparts improved machinability.

BASE

A class of chemical compounds whose aqueous solution has a pH greater than 7.0.

BIOCIDE

A chemical agent which kill microorganisms.

BIOSTAT

A chemical agent which prevents microorganisms from growing.

BLACK OILS

A dark-colored lubricating oil which is used for the lubrication of machine parts under exposed conditions.

BOUNDARY LUBRICATION

The state of lubrication which exists when operating conditions, pressure, temperature or design are not favorable to the formation of the lubricating oil wedge, or to provide a thick oil film, also where the laws of fluid-film lubrication do not apply.  At best, a condition of thin film lubrication exists as the oil does little more than fill the irregularities on the surfaces, with the result that intermittent metal-to-metal contact can be expected.  The best protection under conditions of boundary lubrication is oil rich in oiliness and high film strength, which also exhibits extreme pressure properties.

BUILT UP EDGE (BUE)

A piece of work material which has been strain hardened and pressure welded to the cutting edge of a tool.

CENTERLESS GRINDING

A grinder which eliminates the use of centers by providing a bar support under the Workpiece and a supporting control wheel which may or may not be mounted parallel to the grinding wheel.

CHATTER MARKS

Surface imperfections on the work surface usually caused by vibrations of the tool and/or Workpiece.

CHEMICAL COOLANT

A cutting fluid which does not contain any mineral oil; usually a true solution in water or a fine colloidal solution.

CHLORINE

A common extreme pressure (EP) additive used to promote lubrication.

COMPOUND

Chemically speaking, a distinct substance formed by the combination of two or more elements in definite proportions by weight, and possessing physical and chemical properties different from those of the combining elements.

In petroleum, generally connotes fatty oils and similar materials added to lubricants to impart specific desired properties.

COMPOUNDED OIL

Petroleum oil to which; has been added, animal or vegetable oil, or other compounds to impart desired properties and functions.

COOLANT

Liquid used to cool the work and tool, and to prevent rusting or corrosion; cutting fluid or grinding fluid.

CORROSION

Destruction of a metal by chemical or electrochemical reaction with its environment.

COUPLING AGENT

A mutual solvent or co-emulsifier.

CREAMING

A separate supernatant layer or cuff.  This layer is actually an emulsion of higher “actives” concentration than the original emulsion.

CUTTING FLUID

Fluid (liquid, gas or mist) applied to the working parts of a tool or cutter to promote more efficient machining by acting as a coolant and machining lubricant.

CUTTING OIL

A cutting fluid composed entirely of oil and/or compounds which are oil soluble.

CUTTING RAKE

The amount of material removed in a machining operation per unit of time.

DEEP HOLE DRILLING

Any hole longer than four times its diameter is considered a deep hole.

DERMATITIS

Inflammation or redness of the skin.

DUCTILE

Capable of being deformed when cold.

EMULSIFIABLE OIL

A straight oil or blend which contains an emulsifier or coupling agent so it will form a stable emulsion in water.

EMULSIFIER

A material containing two types of molecular groups, one of which will orient in water and the other in oil.  It will thus, tie together two dissimilar liquids.

ESTER

A compound which may be formed by replacement of the acid hydrogen of an acid by a hydrocarbon radical.

EXTREME PRESSURE (EP) ADDITIVE

A compound which reacts with the surface of the metal or tool, forming thin films of metallic compounds (usually, chloride, sulfide, or phosphate) which have relatively low shear-strength.

EXTREME PRESSURE LUBRICATION

See “Boundary Lubrication”.  In addition, withstands much higher pressures and temperatures than a traditional boundary lubricated surface.

FAT

Originally, a naturally occurring compound of fatty acid and glycerin.

FATTY ACID

Any of the series of saturated or unsaturated acids such as stearic, oleic, and palmitic acids which occur in natural fats and oils.

FATTY OILS

Organic oils; the most common are lard oil and sperm oil.

FEED

The maximum thickness of a material per tooth.  The amount of horizontal movement of the tool per revolution of the Workpiece into the Workpieces.

FINES

Particles of insoluble matter which are small enough to pass through the pores of a filter, thereby remaining in the solution after filtration.  Particles which cannot be removed from a solution by simple separation methods.

FINISH

Surface quality or appearance.

FINISHING

The final cuts taken to obtain the accuracy and finish.

FRICTION

The resisting force encountered at the common boundary between two bodies when, under the action of an external force, one body moves or tends to more relative to the surface of the other.

GALVANIC

Pertaining to the flow of electricity flowing as a result of chemical action.

GERMICIDE

Any compound which destroys germs or microorganisms.

HARD WATER

Water that contains certain salts, such as those of calcium or magnesium.  These salts form insoluble deposits with certain components of water soluble cutting fluids.

HYDRODYNAMIC LUBRICATION

Lubrication where the viscosity of the lubricant keeps the surfaces separated by a fluid film.

INHIBITOR

Any compound which slows or prevents such chemical reactions as corrosion or oxidation.

INVERTED EMULSION

A dispersion of droplets of water in oil produced when a small quantity of water is mixed with a relatively large quantity of oil.

LARD OIL

Natural oil prepared from chilled lard or from the fat of swine.

LUBRICANT

Any substance between two surfaces in relative motion used for the purpose of reducing the friction and/or wear between them.

LUBRICATION

The process of reducing friction and wear between two surfaces in relative motion.

MACHINABILITY

The relative difficulty of a machining operation with regard to tool life, surface finish and power consumption.

METALLIC SOAP

The reaction product produced when a fatty acid reacts with metal.

MICELLE

An aggregation of surface active molecules in a solution.

MILLING

The process of producing machined surfaces by progressively removing a predetermined amount of material from the Workpiece which is fed to a rotating milling center.  Two methods of milling are; peripheral milling and face milling.

MINERAL OIL

Any oil of mineral origin such as petroleum oil.

MISCIBLE

Capable of being mixed to yield a solution.

NAPHTHENE

Any of the series of saturated cyclic hydrocarbons of the general formula CnH2n; applied especially to those members occurring in certain kinds of petroleum.

OLEFIN

Any open-chain hydrocarbon having one or more double bonds.

PARAFFIN

Any hydrocarbon of the methane series, especially any of the solid members boiling above 572°F.

RAKE ANGLE

Its function is to direct and facilitate the flow of the chip over the face of the tool and to modify and control the cutting forces which are also affected by the shear angle.

SEMI-SYNTHETIC

A mineral oil containing an emulsifying agent capable of mixing readily with water to form a stable oil-in-water emulsion.  Used in metal cutting operations requiring high lubricating and cooling efficiency.

SOLUBLE OIL

A mineral oil containing an emulsifying agent capable of mixing readily with water to form a stable oil-in-water emulsion.  Used in metal cutting operations requiring high lubricating and cooling efficiency.

STEARATE

A salt or ester of stearic acid.

SULFO-CHLORINATED OIL

Cutting oil containing sulfur and chlorine.  Sometimes the sulfur and chlorine are molecularly bound together.  This can give more efficient metal removal than separate additions of sulfur and chlorine to the oil.

SULFUR

A common extreme pressure (EP) additive used to improve boundary lubrication.

SULFURIZED OIL

Oil to which sulfur or sulfur compounds have been added to improve boundary lubrication.

SURFACE ACTIVE AGENT

Materials capable of lowering surface and interfacial tensions.

SURFACE GRINDING

Done to produce flat surfaces on Workpieces held in contact with a grinding wheel.

SWARF

Metallic particles or abrasive fragments removed by a cutting or grinding tool.  Fines are a type of swarf.

SYNTHETIC FLUIDS

Products which do not contain any mineral oil and usually form true solutions in water.

TREPANNING

Type of drilling process which utilizes multiple rotating cutting tools to produce large holes in metal bar stock or blanks.

THIN FILM LUBRICATION

A condition of lubrication in which the film thickness of the lubricant is such that the friction between the surfaces is determined by the properties of the surfaces as well as the viscosity of the lubricant.

VISCOSITY

Property of a fluid, semi-fluid, or semi-solid substance which causes it to resist flow.

WEAR

The attribution or rubbing away of the surface of a material, such as a tool, as a result of mechanical action.

WETTABILITY

The relative ease with which a liquid spreads over a surface.

WETTING AGENT

An additive which reduces surface and interfacial tension, and thus, facilitates spreading of a fluid over a surface.

WORKPIECE

The part being machined or ground.

WORK HARDENING

A hardening process which may occur during cold working or machining; strain hardening.  This decreases machinability.